Power tool

Abstract

This invention discloses an electric tool. This electric tool solves the problem of motor overheating and burning out during prolonged operation of electric tools in related technologies. During operation, the electric tool utilizes a closed-loop current compensation control circuit formed by the motor, current conversion module, current compensation module, vector control module, and motor drive module. The current compensation module adjusts the reference current input to the vector control module to a minimum and make it adjustable. Furthermore, the closed-loop current compensation control circuit automatically adjusts the compensation current under different loads, effectively reducing bus current and phase current, thereby reducing motor overheating and protecting the motor and electric tool from damage due to excessive or unadjustable current.

Description

Technical Field

[0001] This invention relates to the field of power tool control technology, and more particularly to a power tool. Background Technology

[0002] With the development of power tools, intelligent control technology for power tools is being used more and more widely. For example, controllers are used to drive motors to achieve characteristics such as rapid start-up and smooth braking of power tools.

[0003] However, existing power tools sometimes burn out due to overheating under certain working conditions and prolonged operation. For example, the cord used for trimming grass in a lawnmower is usually quite long, so the winding process takes a long time. As a result, the motor's bus current and phase current are relatively high during the winding process, and the long winding time can easily lead to severe motor overheating and ultimately burnout. Summary of the Invention

[0004] This invention provides an electric tool for controlling the current of the electric tool.

[0005] This invention provides a power tool, which includes:

[0006] Electric motor;

[0007] The current conversion module is used to determine the input current of the current compensation module based on the three-phase current of the motor.

[0008] A current compensation module is used to determine a reference current based on the input current;

[0009] The vector control module is used to determine the control signal based on the reference current, the preset current, the input current, and the angle of the motor.

[0010] The motor drive module is used to adjust the current of the motor according to the control signal, so as to drive the motor to rotate.

[0011] Optionally, the current compensation module includes a first reactive power output unit, a second reactive power output unit, and a reactive power controller;

[0012] The first reactive power output unit is used to process the input current and the first input voltage, and output the first reactive power; the second reactive power output unit is used to process the input current and the second input voltage, and output the second reactive power; the reactive power controller is used to adjust the output of the reference current according to the reactive power deviation and the preset target reactive power; wherein, the first input voltage is determined based on the angle of the motor, the second input voltage is determined based on the angle of the motor, and the reactive power deviation is the difference between the first reactive power and the second reactive power.

[0013] Optionally, the preset target reactive power is zero.

[0014] Optionally, the current compensation module includes a first angle control unit, a second angle control unit, and an angle signal holding unit;

[0015] The first angle control unit processes the input voltage and outputs a first reference angle, the input voltage being determined based on the angle of the motor; the second angle control unit processes the input current and outputs a second reference angle; the angle signal holding unit outputs the reference current based on the first reference angle and the second reference angle.

[0016] Optionally, the first reference angle is a voltage phase angle or a current phase angle, and the second reference angle is a current phase angle or a voltage phase angle; the angle signal holding unit is a phase-locked loop.

[0017] Optionally, the vector control module includes a first current control unit, a second current control unit, a first conversion unit, and a signal control unit; the preset current includes a first preset current and a second preset current.

[0018] The first current control unit is used to output a first reference voltage to the first conversion unit based on the reference current, the input current and the first preset current;

[0019] The second current control unit is used to output a second reference voltage to the first conversion unit according to the second preset current and the input current;

[0020] The first conversion unit is used to output a third reference voltage based on the first reference voltage, the second reference voltage, and the angle of the motor;

[0021] The signal control unit is used to process the third reference voltage and output the control signal.

[0022] Optionally, the first transformation unit is a Park inverse transformation unit.

[0023] Optionally, the second preset current is zero.

[0024] Optionally, the current conversion module includes a second conversion unit and a third conversion unit. The second conversion unit is used to convert the three-phase current of the motor into a two-phase rotating current; the third conversion unit is used to convert the two-phase rotating current into a two-phase stationary current.

[0025] Optionally, the second transformation unit is a Clark transformation unit, and the third transformation unit is a Park transformation unit.

[0026] This invention provides an electric tool. This electric tool solves the problem of motor overheating and burning out during prolonged operation of electric tools in related technologies. During operation, the electric tool utilizes a closed-loop current compensation control circuit formed by the motor, current conversion module, current compensation module, vector control module, and motor drive module. The current compensation module adjusts the reference current input to the vector control module to a minimum and make it adjustable. Furthermore, the closed-loop current compensation control circuit automatically adjusts the compensation current under different loads, effectively reducing bus current and phase current, thereby reducing motor overheating and protecting the motor and electric tool from damage due to excessive or unadjustable current. Attached Figure Description

[0027] Figure 1 This is a circuit structure block diagram of an electric tool according to an embodiment of the present invention;

[0028] Figure 2 This is a circuit structure block diagram of another power tool in an embodiment of the present invention;

[0029] Figure 3 This is a circuit structure block diagram of another power tool according to an embodiment of the present invention. Detailed Implementation

[0030] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention and not the entire structure.

[0031] Figure 1 This is a circuit structure block diagram of a power tool provided in an embodiment of the present invention. (Reference) Figure 1 The power tool includes: a motor 10; and a current conversion module 20, used to determine the input current I of the current compensation module 30 based on the three-phase current of the motor 10. i Current compensation module 30, used to compensate for input current I i Determine the reference current Ir Vector control module 40, used to control the reference current I r Preset current I s Input current I i The angle θ between the motor 10 and the control signal is determined; the motor drive module 50 is used to adjust the current of the motor 10 according to the control signal to drive the motor 10 to rotate.

[0032] The motor 10 is a three-phase motor. The current conversion module 20 is electrically connected to the motor 10 and is used to acquire the three-phase current of the motor 10 and determine the input current I of the current compensation module 30 based on the three-phase current of the motor 10. i The current compensation module 30 is electrically connected to the current conversion module 20 and is used to acquire the input current I. i And according to the input current I i Determine the reference current I r The vector control module 40 is electrically connected to the current compensation module 30 and is used to obtain the reference current I. r The vector control module 40 is electrically connected to the current conversion module 20 and is used to acquire the input current I. i The vector control module 40 is electrically connected to the motor 10 and is used to obtain the motor angle θ and, based on the obtained reference current I... r Preset current I s Input current I i The angle θ between the motor 10 and the control signal is determined. The motor drive module 50 is electrically connected to the vector control module 40 and the motor 10 respectively, and is used to acquire the control signal and adjust the current of the motor 10 according to the control signal, thereby driving the motor to rotate.

[0033] The motor drive module 50 can be a driver, such as a servo driver or an L298n driver. Preset current I s The settings can be adjusted according to the load conditions of the power tools; no specific limitations are made here.

[0034] In the technical solution of this embodiment, the power tool can be a lawnmower, a product with a low-speed mode, etc. For example, combined with... Figure 1Taking a lawnmower as an example, the cord used for mowing is usually quite long, so the time spent reeling in the cord is relatively long. Furthermore, the motor speed is very low during cord reeling. Without position control and a position encoder, accurate information such as the motor's position and speed cannot be obtained at low speeds, so only open-loop speed control can be used. Therefore, the motor current cannot be effectively controlled during cord reeling, resulting in high bus current and phase current. Combined with the long reeling time, this easily leads to severe motor overheating and potential motor burnout. To address this, the power tool provided in this embodiment of the invention can achieve the following: during the operation of the lawnmower, the current conversion module 20 converts the three-phase current output by the motor 10 into an input current I. i The input is fed into the current compensation module 30 and the vector control module 40. The current compensation module 30 adjusts the input current I according to the input current. i Adjust the output reference current I r And input to vector control module 40, vector control module 40 according to the received input current I i Reference current I r The angle θ of motor 10 and the preset current I s The control signal is adjusted and sent to the motor drive module 50. The motor drive module 50 controls the current of the motor 10 according to the received control signal to drive the motor 10 to rotate. Thus, the motor 10, the current conversion module 20, the current compensation module 30, the vector control module 40 and the motor drive module 50 form a closed-loop current compensation control circuit, which can automatically adjust the magnitude of the compensation current under different loads, effectively reduce the bus current and phase current, thereby reducing motor heating and protecting the motor and power tools.

[0035] It should be noted that the motor speed of a lawnmower is usually relatively slow during the reel-in phase, which can easily lead to motor overheating and burnout. Therefore, the main controller of the lawnmower can determine whether the motor is operating at low speed and high torque. When it is operating at low speed (e.g., less than or equal to 100 rpm) and high torque (e.g., greater than or equal to 1 N·m), the control scheme of this embodiment can be used to implement current compensation control for the motor. When it is not operating at low speed and high torque, it can switch to conventional current control (no current compensation required). Alternatively, the main controller of the lawnmower can determine whether the motor is in open-loop speed-driven strong drag mode. When it is in open-loop speed-driven strong drag mode, the control scheme of this embodiment can be used to implement current compensation control for the motor. When it is not in open-loop speed-driven strong drag mode, it can switch to conventional current control (no current compensation required).

[0036] The technical solution of this embodiment provides an electric tool, which includes a motor; a current conversion module for determining the input current of a current compensation module based on the three-phase current of the motor; a current compensation module for determining a reference current based on the input current; a vector control module for determining a control signal based on the reference current, a preset current, the input current, and the motor angle; and a motor drive module for adjusting the motor current according to the control signal to drive the motor to rotate. This electric tool solves the problem of motor overheating and burning out due to prolonged operation of electric tools in the prior art. During operation, the electric tool forms a closed-loop current compensation control circuit through the motor, current conversion module, current compensation module, vector control module, and motor drive module. The adjustment function of the current compensation module minimizes and adjusts the reference current input to the vector control module. Furthermore, the closed-loop current compensation control circuit automatically adjusts the magnitude of the compensation current under different loads, effectively reducing bus current and phase current, thereby reducing motor overheating and protecting the motor and electric tool from damage due to excessive or unadjustable current.

[0037] Figure 2 This is a circuit structure block diagram of another power tool provided in an embodiment of the present invention. Optionally, as one implementation, refer to... Figure 2 The current compensation module 30 includes a first reactive power output unit 31, a second reactive power output unit 32, and a reactive power controller 33.

[0038] The first reactive power output unit 31 is used to output the input current I. r First input voltage V i1 The system processes the input current I and outputs the first reactive power P1; the second reactive power output unit 32 is used to process the input current I. r Second input voltage V i2 The system processes the reactive power and outputs a second reactive power P2; the reactive power controller 33 adjusts the output reference current I based on the reactive power deviation and the preset target reactive power P0. r ; where the first input voltage V i1 Based on the angle of motor 10, the second input voltage V i2 Based on the angle θ of motor 10, the deviation of reactive power is the difference between the second reactive power P2 and the first reactive power P1.

[0039] Wherein, the first reactive power P1 can be the reactive power of motor 10 during operation, and is related to the input current I. r and the first input voltage V i1 The specific details can be obtained using the formulas relating power, current, and voltage. The second reactive power P2 can be the reactive power stored in the internal windings of motor 10, and is related to the input current I. rSecond input voltage V i2 The specific details can be obtained from the formulas relating power, current, and voltage.

[0040] Wherein, the first input voltage V i1 Second input voltage V i2 It can be obtained by performing an inverse Park transformation on the angle of motor 10.

[0041] Specifically, in order to reduce motor heat generation, it is necessary to achieve minimum and adjustable current under different loads. Therefore, a current compensation module 30 is set up to output a reference current I. r Minimum and adjustable. Since current is proportional to reactive power, in order to achieve the reference current I... r The system is designed to be minimum and adjustable, and includes a first reactive power output unit 31, a second reactive power output unit 32, and a reactive power controller 33. The reactive power controller 33 continuously adjusts the reactive power deviation to approach a preset target reactive power, achieving a zero difference between the reactive power deviation and the preset target reactive power, thereby realizing the reference current I. r Minimum and adjustable. The closer the reactive power deviation is to the preset target reactive power, the better it is to balance the reactive power stored in the windings of the motor 10 and the reactive power of the motor 10 during operation, and the better it is to minimize reactive power and maximize the utilization rate of motor input power.

[0042] Optionally, the target reactive power P0 is preset to zero.

[0043] The reactive power deviation represents the total reactive power of the system. To minimize the total reactive power, a preset target reactive power P0 is set to zero. This causes the reactive power controller 33 to adjust the reactive power deviation according to the target of zero, ultimately achieving a dynamic balance between the second reactive power P2 and the first reactive power P1. This satisfies the energy exchange required for normal motor operation while maximizing motor efficiency. Furthermore, since different motors have different target saliency rates, the preset target reactive power P0 may not necessarily be zero; it can be other values. The specific setting can be determined based on actual conditions and is not limited here.

[0044] Optionally, continue to refer to Figure 2 The current conversion module 20 includes a second conversion unit 21 and a third conversion unit 22. The second conversion unit 21 is used to convert the three-phase current of the motor 10 into a two-phase rotating current; the third conversion unit 22 is used to convert the two-phase rotating current into a two-phase stationary current.

[0045] For example, assuming motor 10 is a three-phase motor, let the three-phase currents output by its a-axis, b-axis and c-axis be I respectively. a I b, and I c Three-phase current I a I b , and I c After passing through the second transformation unit 21, it can be converted into rotating currents corresponding to the α-axis and β-axis, such as I. α and I β The rotating currents corresponding to the α and β axes are converted into stationary currents corresponding to the q and d axes by the third transformation unit 22, such as I. i1 and I i2 .

[0046] Optionally, the second transformation unit 21 is a Clark transformation unit, and the third transformation unit 22 is a Park transformation unit.

[0047] Optionally, continue to refer to Figure 2 The vector control module 40 includes a first current control unit 41, a second current control unit 42, a first conversion unit 43, and a signal control unit 44; the preset current I... s Including the first preset current I s1 Second preset current I s2 The first current control unit 41 is used to determine the reference current I. r Input current I i and the first preset current I s1 Output first reference voltage V r1 The first conversion unit 43; the second current control unit 42 is used to adjust the second preset current I according to the second preset current I. s2 and input current I i Output second reference voltage V r2 To the first conversion unit 43; the first conversion unit 43 is used to convert the first reference voltage V r1 Second reference voltage V r2 The third reference voltage V is output from the angle of the motor. r3 Signal control unit 44, used for controlling the third reference voltage V r3 It processes the data and outputs control signals.

[0048] In this process, the three-phase current output by motor 10 is transformed sequentially by the second transformation unit 21 and the third transformation unit 22, resulting in static currents corresponding to the q-axis and d-axis, such as I. i1 and I i2 At this time, the input current to the vector control module 40 is the q-axis input current I. i1 and the input current I along the d-axis i2 The first current control unit 41 is used to adjust the current compensation of the q-axis, and the second current control unit 42 is used to adjust the current compensation of the d-axis. The first preset current I... s1The target adjustment current for q-axis current compensation, the second preset current I s2 The target adjustment current for d-axis current compensation. Typically, the first preset current I... s1 The magnitude is related to the load, the second preset current I s2 The second preset current is usually set to zero. However, in other possible implementations, the second preset current can also have other values, which can be set according to the actual situation. Specifically, the first current control unit 41 will set the reference current I... r With the first preset current I s1 The sum of these, along with the q-axis input current I. i1 The first reference voltage V is obtained by subtracting the two values ​​and adjusting the result using a PI proportional-integral controller. r1 The second current control unit 42 will set the second preset current I. s2 Input current I along the d-axis i2 The difference is subtracted, and the result is adjusted by a PI proportional-integral controller to obtain the second reference voltage V. r2 .

[0049] Among them, the first reference voltage V r1 The voltage along the q-axis, and the second reference voltage V. r2 This is the voltage along the d-axis. The first transformation unit 43 is used to convert the first reference voltage V along the q-axis. r1 Based on the phase angle of the motor, the voltage of the α-axis is converted, and the second reference voltage V of the d-axis is... r2 The voltage is converted to the β-axis voltage based on the phase angle of the motor. Optionally, the first conversion unit 44 is a Park inverse conversion unit.

[0050] The signal control unit 44 can be a PWM pulse width modulator, used to control the third reference voltage V. r3 The signal is processed and a PWM control signal is output to control the motor drive module 50. The third reference voltage V... r3 These are the voltages along the α and β axes.

[0051] Among them, the first preset current I s1 The setting can be adjusted according to the load conditions of the power tool. For example, under no-load conditions, it generally does not exceed 10% of the rated current; under light load conditions, it can be set to 10% to 50% of the rated current; and under heavy load conditions, it can be set to 50% to 80%. The specific value can be set according to the actual situation, and no specific limit is made here.

[0052] In the technical solution of this embodiment, the implementation process of the power tool is as follows: For example, taking a lawnmower as an example, when the motor speed is at low speed and high torque (for example, when the lawnmower enters a low-speed winding working state), the second conversion unit 21 converts the three-phase current I of the motor 10 into a high-torque motor. a I b , and Ic Converted into rotating currents corresponding to the α and β axes, such as I α and I β ;I α and I β The current is converted into a stationary current corresponding to the q-axis and d-axis by the third transformation unit 22, such as I. i1 and I i2 Among them, the current I along the α axis α The current Iβ on the β-axis is input to the first reactive power output unit 31 and the second reactive power output unit 32. At this time, the input current of the current compensation module 30 is I. α and I β ; q-axis current I i1 The current I on the d-axis is input to the first current control unit 41. i2 The input is sent to the second current control unit 42; the first reactive power output unit 31 outputs power according to the first input voltage V. i1 Current I along the α axis α and the current I along the β axis β The first reactive power output unit P1 outputs reactive power, and the second reactive power output unit 32 outputs reactive power based on the second input voltage V. i2 Current I along the α axis α and the current I along the β axis β The second reactive power P2 is output; the reactive power controller 33 adjusts the output reference current I according to the deviation of the reactive power P2, the first reactive power P1 and the preset target reactive power P0. r The first current control unit 41 determines the reference current I based on the reference current I. r First preset current I s1 and the q-axis input current I i1 Adjust the first reference voltage V of the output r1 The current is input to the first conversion unit 43, and the second current control unit 42 inputs the current according to the second preset current I. s2 Input current I along the d-axis i2 Adjust the output second reference voltage V r2 And output to the first conversion unit 43; the first conversion unit 43 converts the first reference voltage V of the q-axis r1 Based on the phase angle of the motor, the voltage of the α-axis is converted, and the second reference voltage V of the d-axis is... r2The phase angle of the motor is converted into a voltage on the β axis. The signal control unit 44 outputs a control signal based on the voltages on the α and β axes to drive the motor drive module 50 to adjust the motor current. Thus, a closed-loop current compensation control circuit is formed by the motor 10, current conversion module 20, current compensation module 30, vector control module 40, and motor drive module 50. Furthermore, the first reactive power output unit 31, the second reactive power output unit 32, and the reactive power controller 33 adjust the dynamic balance between the reactive power P2 stored in the motor's internal windings and the reactive power P1 generated during motor operation, ensuring that the reactive power deviation is zero and that the reference current I input to the vector control module 40 is... r The current is minimized and adjustable, and through a closed-loop current compensation control circuit, the motor current can be minimized and adjusted under different loads, thereby protecting the motor and power tools from damage due to excessive or unadjustable current.

[0053] Figure 3 This is a circuit structure block diagram of another power tool provided in an embodiment of the present invention. Optionally, in one implementation, the current compensation module 30 includes a first angle control unit 34, a second angle control unit 35, and an angle signal holding unit 36; the first angle control unit 34 is used to control the input voltage V. i0 Processing is performed to output the first reference angle θ1, and the input voltage V is... i0 The angle θ of motor 10 is determined; the second angle control unit 35 is used to control the input current I. i The process is performed to output a second reference angle θ2; the angle signal holding unit 36 ​​is used to output a reference current I based on the first reference angle θ1 and the second reference angle θ2. r .

[0054] Wherein, the input voltage V i0 It can be obtained by performing an inverse Park transformation on the angle θ of motor 10. For example, the voltage V on the α axis can be obtained by performing an inverse Park transformation. α and the voltage V along the β axis β The first angle control unit 34 determines the voltage V along the α axis. α and the voltage V along the β axis β The ratio of these values ​​can be used to obtain the first reference angle θ1.

[0055] Among them, since the three-phase current output by motor 10 is converted into rotational currents corresponding to the α-axis and β-axis by the second conversion unit 21, such as I α and I β ;I α and I β The current is converted into a stationary current corresponding to the q-axis and d-axis by the third transformation unit 22, such as I. i1 and I i2At this time, the input current of the current compensation module 30 is I. α and I β The second angle control unit 35 determines the current I along the α axis. α and the current I along the β axis β The ratio can be used to obtain the second reference angle θ2.

[0056] Optionally, the first reference angle θ1 is a voltage phase angle or a current phase angle, and the second reference angle θ2 is a current phase angle or a voltage phase angle; the angle signal holding unit 36 ​​is a phase-locked loop.

[0057] For example, taking the first reference angle θ1 as the voltage phase angle and the second reference angle θ2 as the current phase angle, the voltage phase angle can be considered as the reference angle, and the current phase angle as the actual angle. If the difference between the reference angle and the actual angle remains constant, the angular velocity of the motor rotor will be synchronized with the reference value; otherwise, the motor rotor will run away, increasing current loss. Therefore, to avoid increased current damage due to rotor runaway, the first reference angle θ1 and the second reference angle θ2 are adjusted by the angle signal holding unit 36 ​​to minimize their deviation, thereby ensuring that the reference current I input to the vector control module 40 is... r The current is minimized and adjustable, and through a closed-loop current compensation control circuit, the motor current can be minimized and adjusted under different loads, thereby protecting the motor and power tools from damage due to excessive or unadjustable current.

[0058] It should be noted that current compensation control can also be performed using the first reference angle θ1 as the current phase angle and the second reference angle θ2 as the voltage phase angle, that is, using the current phase angle as the reference angle and the voltage phase angle as the actual angle. The specific settings can be adjusted according to the actual situation, and no specific limitations are made here.

[0059] The angle signal holding unit 36 ​​is also used to keep the difference signal between the first reference angle θ1 and the second reference angle θ2 constant, thereby improving the stability of signal transmission and ensuring the accuracy of current compensation.

[0060] In the technical solution of this embodiment, the implementation process of the power tool is as follows: For example, taking a lawnmower as an example, when the motor speed is at low speed and high torque (for example, when the lawnmower enters a low-speed winding working state), the second conversion unit 21 converts the three-phase current I of the motor 10 into a high-torque motor. a I b , and I c Converted into rotating currents corresponding to the α and β axes, such as I α and I β ;I α and I β The current is converted into a stationary current corresponding to the q-axis and d-axis by the third transformation unit 22, such as I. i1 and Ii2 Among them, the current I along the α axis α The current I of the β-axis is input to the first angle control unit 34 and the second angle control unit 35. β The input current to the first angle control unit 34 and the second angle control unit 35 is I. α and I β ; q-axis current I i1 The current I on the d-axis is input to the first current control unit 41. i2 The input is sent to the second current control unit 42; the first angle control unit 34 adjusts the input voltage V according to the input voltage V. i0 The first reference angle θ1 is output, and the second angle control unit 35 outputs the current I along the α axis. α and the current I along the β axis β Output a second reference angle θ2; the angle signal holding unit 36 ​​adjusts the output reference current I according to the first reference angle θ1 and the second reference angle θ2. r The first current control unit 41 determines the reference current I based on the reference current I. r First preset current I s1 and the q-axis input current I i1 Adjust the first reference voltage V of the output r1 The current is input to the first conversion unit 43, and the second current control unit 42 inputs the current according to the second preset current I. s2 Input current I along the d-axis i2 Adjust the output second reference voltage V r2 And output to the first conversion unit 43; the first conversion unit 43 converts the first reference voltage V of the q-axis r1 Based on the phase angle of the motor, the voltage of the α-axis is converted, and the second reference voltage V of the d-axis is... r2 The phase angle of the motor is converted into a voltage on the β axis. The signal control unit 44 outputs a control signal based on the voltages on the α and β axes to drive the motor drive module 50 to adjust the motor current. Thus, a closed-loop current compensation control circuit is formed by the motor 10, current conversion module 20, current compensation module 30, vector control module 40, and motor drive module 50. Adjusted by the first angle control unit 34, second angle control unit 35, and angle signal holding unit 36, the difference between the reference angle and the actual angle remains constant, ensuring that the angular velocity of the motor rotor is synchronized with the reference value. This prevents the motor rotor from running away and minimizes current loss, thus ensuring the reference current I input to the vector control module 40 is obtained. r The current is minimized and adjustable, and through a closed-loop current compensation control circuit, the motor current can be minimized and adjusted under different loads, thereby protecting the motor and power tools from damage due to excessive or unadjustable current.

[0061] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A power tool, characterized in that, include: Electric motor; The current conversion module is used to determine the input current of the current compensation module based on the three-phase current of the motor. A current compensation module is used to determine a reference current based on the input current; The vector control module is used to determine the control signal based on the reference current, the preset current, the input current, and the angle of the motor. A motor drive module is used to adjust the current of the motor according to the control signal in order to drive the motor to rotate; The current compensation module includes a first reactive power output unit, a second reactive power output unit, and a reactive power controller. The first reactive power output unit processes the input current and the first input voltage to output the first reactive power; the second reactive power output unit processes the input current and the second input voltage to output the second reactive power; the reactive power controller adjusts the output of the reference current according to the reactive power deviation and the preset target reactive power; wherein, the first input voltage is determined based on the angle of the motor, the second input voltage is determined based on the angle of the motor, and the reactive power deviation is the difference between the first reactive power and the second reactive power.

2. The power tool according to claim 1, characterized in that, The preset target reactive power is zero.

3. The power tool according to any one of claims 1 to 2, characterized in that, The vector control module includes a first current control unit, a second current control unit, a first conversion unit, and a signal control unit; the preset current includes a first preset current and a second preset current. The first current control unit is used to output a first reference voltage to the first conversion unit based on the reference current, the input current and the first preset current; The second current control unit is used to output a second reference voltage to the first conversion unit according to the second preset current and the input current; The first conversion unit is used to output a third reference voltage based on the first reference voltage, the second reference voltage, and the angle of the motor; The signal control unit is used to process the third reference voltage and output the control signal.

4. The power tool according to claim 3, characterized in that, The first transformation unit is the inverse Park transformation unit.

5. The power tool according to claim 3, characterized in that, The second preset current is zero.

6. The power tool according to any one of claims 1 to 2, characterized in that, The current conversion module includes a second conversion unit and a third conversion unit. The second conversion unit is used to convert the three-phase current of the motor into a two-phase stationary current; the third conversion unit is used to convert the two-phase stationary current into a two-phase rotating current.

7. The power tool according to claim 6, characterized in that, The second transformation unit is a Clark transformation unit, and the third transformation unit is a Park transformation unit.

8. A power tool, characterized in that, include: Electric motor; The current conversion module is used to determine the input current of the current compensation module based on the three-phase current of the motor. A current compensation module is used to determine a reference current based on the input current; The vector control module is used to determine the control signal based on the reference current, the preset current, the input current, and the angle of the motor. The motor drive module is used to adjust the current of the motor according to the control signal to drive the motor to rotate; the current compensation module includes a first angle control unit, a second angle control unit and an angle signal holding unit; The first angle control unit is used to process the input voltage and output a first reference angle, wherein the input voltage is determined based on the angle of the motor; the second angle control unit is used to process the input current and output a second reference angle. The angle signal holding unit is used to output the reference current according to the first reference angle and the second reference angle.

9. The power tool according to claim 8, characterized in that, The first reference angle is the voltage phase angle, and the second reference angle is the current phase angle; the angle signal holding unit is a phase-locked loop.

10. The power tool according to any one of claims 8 to 9, characterized in that, The vector control module includes a first current control unit, a second current control unit, a first conversion unit, and a signal control unit; the preset current includes a first preset current and a second preset current. The first current control unit is used to output a first reference voltage to the first conversion unit based on the reference current, the input current and the first preset current; The second current control unit is used to output a second reference voltage to the first conversion unit according to the second preset current and the input current; The first conversion unit is used to output a third reference voltage based on the first reference voltage, the second reference voltage, and the angle of the motor; The signal control unit is used to process the third reference voltage and output the control signal.

11. The power tool according to any one of claims 8 to 9, characterized in that, The current conversion module includes a second conversion unit and a third conversion unit. The second conversion unit is used to convert the three-phase current of the motor into a two-phase stationary current; the third conversion unit is used to convert the two-phase stationary current into a two-phase rotating current.

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